Air-relief valve.



No 775,661. PATENTED NOV. 22, 1904. J. T. LEWIS.

AIR RELIEF VALVE. APPLIOATION FILED JULY 18, 1904.

do MODEL".

I l W V M \A "a 11742, .Y A i UNITED STATES Patented November 22, 1904.

' PATENT @rricn.

AIR-RELIEF VALVE.

SPECIFICATION forming part of Letters Patent No.' '77 5,661, datedNovember 22, 1904.

Application filed July 18, 1904:.

To all whom it may concern.-

Be it known that I, J AMES THouAs Lnwrs, a citizen of the United States,residing at Chattanooga, in the county of Hamilton and State ofTennessee, have invented a new and useful Air-Relief Valve for AutomaticAir-Brakes, of which the following herein set out is a specification.

The existing method of applying air-brakes to railroad-trains isunsatisfactory in so far as the locomotivebrakes come into action andare released simultaneously with those on the remainder of the train.Applying the air-brakes frequently causes the locomotivewheels to becompletely locked, so that they slide on the rails, thereby flatteningthem, and at the present time there is no adequate release of thelocomotive-brakes without releasing the brakes on the whole train. Myinvention obviates this trouble and puts the engineer in control 'of hisengine-brakes independently of the rest of the train. In other words,when the engineer has applied the airbrakes to his train he caninstantly release or govern the pressure of the brakes on his enginewithout interfering in any way with any other part of the train.

My invention relates to improvements in the operative mechanism oftrain-brakes or any other device in which compressed air is used; andthe objects of my improvement are to allow the engineer or operator tohave independent control of the locomotive-brakes in the case of a trainwithout interfering with the operation of thebrakes on the rest of thetrain. I attain these objects by the mechanism illustrated in theaccompanying drawings, in which- Figure 1 is a vertical section of theentire machine; Fig. 2, a top view of the same; and Fig. 3 a reductionof Fig. 1 with the lever thrown down, showing the machine in operation.

Similar letters refer to similar parts throughout the several views.

The chamber of the device is made in two piecesthe lower part A and theupper part B. Connection is made with a suitable pipe C, threaded intothe lower part of A, as shown. This connection is made between SerialNo. 217,095. (No model.)

what is known as the triple and the brakecylinder in the brake-cylinderpipe. B has its upper part threaded to receive the fitting D, which maybe screwed up or down within certain limits and held securely in placeby the jam-nuts E E. The fitting D has a fork in one end, in which ishinged the leverF by means of the bolt G. The opposite end of D isfitted with a guide to prevent the lever F from becoming disengaged fromthe valvestem H. A and B are threaded together, so as to make anair-tight joint. The partition B has in its lower surface an openinginto which the valve H is ground to an air-tight joint. The valve H isheld in position by the spring I and is guided by the valve-stem H. Theupper surface of'B is provided with the holes J J toallow the egress ofexhaustair when the machine is in operation. The lower part of. A isexteriorly threaded to receive the bracket K, which is held in anydesired position by the lock-nut L. The bracket K and the lever F areshown brokenaway for convenience.

In the case of a train-brake theoperation of my invention is as follows:The air having been turned on the brakes are automatically applied toall the cars and to the locomotive-wheels. By depressing the lever F thevalve H is unseated, allowing the air to escape through the opening Dand the holes J J. As soon as the lever F is released the spring I andthe pressure of the air force the valve H into its seat again, thusallowing the locomotive brake to come into operation again. Itwillreadily be seen that the airrelease is completely under the control ofthe operator, allowing him to entirely release the engine-brakes orapply such pressure upon them as he may see fit.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The combination in an air-brake, or other 7 device, operated bycompressed air, of an airrelief Valve made in two pieces, the lower halfbeing internally threaded to provide a suitable connection for the inletair-pipe and externally threaded to provide for an adjustable bracket;and the upper half provided with a partition containing in its lowersurface, a

' seat for an air-relief valve, apertures for the 5 the adjustablefitting D and the lever F subrelease of exhaustair, and an exteriorly- Istantially as set forth. I0

threaded projection which serves, at the same In testimony WhereofIhavesigned my name time for a guide to the valve-stem and also, in thepresence of two subscribing Witnesses.

as a means for raising and fixing in place the JAMES THOMAS LEWIS. leverfulcrum and guide. Witnesses:

2. The combination in an air-relief valve of i A. R. MCKENZIE,

the body A, B, with the valve-stem H, H, l P. L. THOMPSON.

